Apparatus for continuous electroplating

ABSTRACT

Apparatus for electroplating items passing through an electrolyte on a continuous conveyor system including means for masking off portions of the items and further including means for automatic loading and unloading of the items to the conveyor system. The items are electrically isolated from one another, and each is individually electrically connected to a power source while in the electroplating bath.

arch 14, N72 (5. D. WELTER 3,649,567

APPARATUS FOR CONTINUOUS ELECTROPLATING Filed July 13, 1970 2 Sheets-Sheet l INVENTOR. GARY D. WELTER ROBERT L. HARRINGTON ATTORNEY March 14, 1972 G. D. WELTER APPARATUS FOR CONTINUOUS ELECTROPLATING Filed July 13, 1970 2 Sheets-Sheet 2 INVENTOR. GARY D. WELTER ROBERT L. HARRINGTON ATTOR N EY United States Patent 3,649,507 APPARATUS FOR CONTINUOUS ELECTROPLATING Gary D. Welter, Oregon City, reg., asslgnor to Omark Industries, Inc., Portland, Oreg. Filed July 13, 1970, Ser. No. 54,494 Int. Cl. B65g 49/02 US. Cl. 204-202 8 Claims ABSTRACT OF THE DISCLOSURE HISTORY This invention relates to electroplating and more particularly to a fully automatic apparatus for electroplat ng.

Chrome plating is done by the process of electroplating. Very generally a conductive bar and the item to be plated are immersed in a solution containing chromium. The bar and the item are connected to an electrical source establishing the bar as the anode and the item the cathode. Current fiow from the bar to the item causes chromium from the solution to be deposited onto the item.

To achieve the desired plating, the solution or electrolyte must be controlled to maintain the proper balance of chromium in solution, it must be kept at the proper temperature, the current flow must be carefully regulated, the spacing between the anode and item must be accurately maintained and the process must be carefully timed.

Where items are not to be completely chrome plated they must be masked. Such masked chrome plating is desired for the cutting links of saw chain. Heretofore the chrome plating process involved manually placing the individual cutting links in special racks. The holders in which the cutters are placed cover the portion that is not to be plated. The racks are then lowered into a vat of the electrolyte solution which is controlled to retain the proper solution balance and temperature. After the proper time span the racks are removed from the vat and rinsed. The cutters are then manually removed from the racks.

The above described process is slow and requires multiple handling, both of which are undesirable in saw chain manufacturing where thousands of such cutters are produced by the hour. The present invention is believed to provide the first successful fully automatic chrome plating apparatus capable of discriminate plating. Very briefly the preferred embodiment of the invention includes an end less conveyor having spring clip means for holding the cutter links. At one point along the conveyor pathway means are provided to open the spring clip and automatically insert a cutter link. With the spring clip closed only the portion of the cutter link to be plated is exposed. The conveyor then carries the links down into a trough which contains the electrolyte, carefully controlled in both temperature and solution strength at a remote vat from which the electrolyte is continuously circulated to the trough. A bar in the trough is carefully positioned relative to the conveyor path and constitutes the anode. A bar above the conveyor path and over the trough carries the cathode current. A leaf spring carried by the conveyor for each spring clip establishes a sliding contest with the overhead bar and a conductor between the leaf spring and the spring clip conducts the current from the bar to the spring clip and to the cutter link held therein. As the cutter link is carried down the trough the desired current is steadily maintained between the anode bar and cutter link. By carefully controlling the speed of the belt the proper time span is achieved. The links are then carried by the conveyor through a bath and then dumped from the conveyor.

Having thus generally described the invention, it will be described in more detail by reference to the accompanying drawings wherein:

FIG. 1 is a plan view of a saw chain cutter link chrome plating apparatus embodying the invention, portions of which are removed for clarity.

FIG. 2 is a side view of the apparatus shown in FIG. 1;

FIG. 3 is a section view taken on section lines 33 of FIG. 1;

FIG. 4 is a section view taken on lines 44 of FIG. 3;

FIG. 5 is a section view taken on lines 5-5 of FIG. 1; and

FIG. 6 is a view taken on lines 66 of FIG. 2.

With reference to the drawings, the conveyor 10 includes interconnected roller chain links 12 with a top plate 14 carried by each link, see FIGS. 3-5. A yoke 16 of non-conductive material is fastened to each plate 14. A conductive leaf spring 18 is connected by conductive screw 20 to the top of the yoke 16. As particularly shown in FIG. 3 a conductive spring clip 22 is fastened to each end of the yoke 16 by a conductive screw 24. An electrical conductor 26 interconnects screws 20 and 24 to thereby ggnductively interconnect leaf spring 18 with spring clip Referring now to FIGS. 1 and 2, it will be seen that conveyor 10 is formed into an endless loop that is driven by a drive sprocket 28 that in turn is driven by motor 30. From the drive sprocket 28 the conveyor passes over a first idler sprocket 32, is guided by a guide rail 34 through a trough 36, passes over second and third idler sprockets 38 and 40, through a wash tank 42, over reverse idler gcgller 44, past a loader 46 and back to the drive sprocket 'Referring to FIGS. 3 and 4, a pair of troughs 36 supported by brace 48 are positioned to receive the yoke arms 16a. A conductive bar 50 is mounted in the trough and extends substantially along the trough adjacent the path of the yoke arms 16a while maintaining the appropriate spacing from the pathway. Although not shown it will be understood that the bar is appropriately mounted with electrical connections to establish the anode for the electrolytic process.

The braces 48 extend over the trough and conveyor as shown in FIG. 3. A channel member 54 is carried by the braces 48. A bus bar 56 is fastened by screws 58 to the channel member. Depending from the channel member are rails 60 with self lubricating slides 62. These slides are adapted to engage the shoulder portion 16b of the yokes 16 to force the yoke arms 16a to the proper depth within the troughs 36. As will be seen from FIG. 2, the entire structure including channel member, rails and slides have an inclined end portion with which the conveyor is received and then guided down to the trough. As can be seen in FIG. 3, the leaf spring 18 slidingly engages the bus bar 56. The bus bar 56 is insulated from the channel member by layer 64 and the appropriate electrical connections are provided to establish the bus bar with'the cathode current for electrolyte process. It may be desired to mount a cover over the troughs to protect workers, etc. Such a cover is not shown herein for purposes of clarity.

Loading of cutter links onto the conveyor will now be explained by reference to FIGS. 1, 2, 4 and 6. A hopper 66 is provided on each side of the conveyor. Such hoppers are in common use for chain manufacturing. They receive a quantity of cutter links and by using gravity and centrifugal forces spin the links onto a track 68 which receives the links oriented in one position only. The track guides the links to a loader shown in FIG. 6. The loader is also a common item used in saw chain manufacturing. It is adapted to receive a cutter link from the track. The spring clip 22 is opened by a pin 70. The pin 70 is slidably held in the yoke 16 with its end protruding through the yoke arm 16a when the spring clip is closed. As shown in FIG. 6 the yoke is passed under a cam arm 72 (note the yoke is inverted on its return to the drive sprocket) whereupon the pin 70 is pushed through the yoke. arm. The head of the pin engages the spring clip and opens it for receiving a cutter link. A micro switch shown schematically at 74 is tripped by the yoke 16 when properly positioned to trigger the loader. As air operated piston 76 in the loader pushes the cutter between the opened spring clip and yoke arm. The pin 70 then passes the cam arm 72 and the spring clip 22 securely grips the cutter link.

Unloading the cutter links from the conveyor is illustrated in FIGS. 2 and 5. A second cam arm 78 is positioned as the conveyor leaves the second idler sprocket to release the spring clip and drop the cutter links into the wash tank 42. A conveyor 82 carries the cutter links from the wash tank and deposits them in a receiving tray 84.

OPERATION A source of the electrolyte is provided from a vat where temperature and solution are automatically controlled. The electrolyte solution is circulated through the trough by tubes 86 and 88 thereby maintaining close control over temperature and strength. A quantity of unplated cutters is dumped into the hopper 66. The cutters are properly oriented automatically and fed through the track 68 to the loader 46. As a yoke 16 passes the loader, it is engaged by cam arm 72 to release the spring clip 22. Then the yoke trips the micro switch 74 and a cutter link is inserted under the spring clip. The configuration of the spring clip is such that the areas that are not to be chrome plated are appropriately masked by the spring clip.

As the yoke 16 travels over the first idler sprocket the shoulder portions are engaged by the slides 62 of the rails 60 and the arm 16a is immersed in the electrolyte. At this point leaf spring 18 slidably engages the bus bar 56 and current is conducted through conductor 26 to the spring clip 22 and in turn the cutter link. The cutter link travels through the trough at a fixed distance from the anode bar 50. With the cutter link established as the cathode the chromium from the electrolyte is deposited on the exposed surface areas of the cutter. The time of electroplating is controlled by the speed of the drive sprocket and the length of the trough. It is common in electroplating processes to initially establish a reverse current, i.e. establish the item to be electroplated as the anode. This is done to clean the surface. It will be understood that this can be accomplished in the present process by providing a short segment of the bus bar 56 and conductive bar 50 with reversed polarity.

After the proper time interval the cutter link reaches the end of the trough where the rail permits the yoke to be drawnfrom the trough. As the conveyor passes over the second idler sprocket a second cam arm is engaged by the pin 70 and the spring clip is opened. The cutter link then falls by gravity into a wash tank and as previously described conveyed to a receiving tray 84. The conveyor then also passes through the wash tank and toward the loader to receive further cutters.

It will be understood that persons skilled in the art and having knowledge of the present disclosure will be capable of making numerous changes and modifications without departing from the scope of the invention. Therefore it is to be understood that the invention is limited only by the claims appended hereto.

What is claimed is:

1. An apparatus for electroplating comprising; an endless conveyor defining a pathway, an elongated trough containing an electrolyte solution along a portion of the pathway, mounting means for mounting a series of Work pieces to the conveyor, insulating means between the work pieces in the series of work pieces, drive means for continuous driving of the conveyor along said pathway, guide means for guiding the work pieces carried by the conveyor through the trough, a bar mounted in the trough adjacent and spaced from the path of the workpiece guided through the trough, means electrically connecting the bar to a power source to establish the bar as an anode, and means independently and selectively connecting each work piece to a power source to establish the work piece as a cathode while being guided through the trough and to disconnect the work piece from the power source while out of the trough.

2. An apparatus as defined in claim 1 wherein said mounting means includes masking means to mask portions of the work piece for exposing selected areas only to the electrolyte contained in the trough.

3. An apparatus as defined in claim 2 wherein the mounting means and masking means comprises a spring clip for gripping and covering the work piece at the portions to be masked.

4. An apparatus as defined in claim 1 wherein the conveyor is comprised of interconnected chain links, a number of non conductive yoke members are afiixed to the chain links, a spring clip on the arm of the yoke for clamping a work piece to the yoke member, a bus bar carrying electrical current fixed over the path of the conveyor as it passes through the trough, a leaf spring connected to each yoke member and adapted to slidingly engage the bar bar for drawing electrical current therefrom, and an electrical conductor electrically connecting the leaf spring and spring clip to conduct electrical current to the work piece.

5. An apparatus as defined in claim 4 wherein a release means is provided along the pathwayat a position following the trough to open the spring clip, automatic loading means positioned along the pathway following the release means for positioning a work piece under the opened spring clip, and actuating means to actuate the release means when passing the loading means, and a switch for the loading means activated as the opened spring clip is positioned for receiving the work piece.

6. An apparatus as defined in claim 5 including a second actuating means to actuate the release means after passing through the trough for releasing the work piece and permitting it to be dropped from the conveyor.

7. An apparatus as defined in claim 4 including a source of electrolyte having a controlled temperature and mixture, and circulatory means for circulating electrolyte from the source through the trough.

8. An apparatus as defined in claim 7 wherein the yoke members are provided with arm portion on each side, a spring clip for each arm of the yoke members ,for electroplating both work pieces held by the yoke member.

References Cited I UNITED STATES PATENTS 3,391,073 7/ 1968 Rusch et al 204202 1,798,994 3/ 1931 Whal-in 204-202 FOREIGN PATENTS 499,837 2/1938 Great Britain 204-203 607,912 12/ 1934 Germany 204-203 JOHN H. MACK, Primary Examiner W. I. SOLOMON, Assistant Examiner US. Cl. X.R.

l34l28; 198-l79; 204-203 

